Screwdriver with an exchangeable tip

ABSTRACT

In a screwdriver with a handle supporting a coaxial rod and a sleeve surrounding the rod, the forward free end of the rod is tapered to engage, when desired, the inside of the tapered forward end of the sleeve. In the forward end of the rod is a slit for receiving the flat rear end of an exchangeable screwdriver tip. When moving the sleeve axially relatively the rod in one direction by means of a control member, the legs of the rod defining the sides of the slit will engage the inside of the tapering sleeve end and press the legs against the tip to secure it to the screwdriver, whereas movement in the opposite direction will release the tip.

United States Patent Sundsten et al.

[ SCREWDRIVER WITH AN EXCHANGEABLE TIP [72] Inventors: Owe WilhelmSundsten, Johanneshov; Karl Bertil Sune Joharmon, I-luddinge, both ofSweden [73] Assignee: Skandinavisk Foto Trade A B,

Nacka, Sweden [22] Filed: May 19, 1971 [21] App]. No.: 144,976

52 U.S.Cl ..14s/50R,279/43 [51] Int. Cl ..B25b 15/02, B23b 31/12 [58]Field of Search 145/50 R, 50 A, 50 B, 50 C, 145/50 F, 66; 279/42, 43,45, 50

[56] References Cited UNITED STATES PATENTS 7 3,121,572 11/1961 Torok..145/5OR [451 Nov. 28, 1972' FOREIGhI PATENTS QR APPLICATIONS 236,23612/1925 Primary Examiner-Robert C. Riordon Assistant Examiner-Mark S.Bicks Attomey -Sa.lter & Michaelson ABSTRACT side of the tapering sleeveend and press the legs against the tip to secure it to the screwdriver,whereas movement in the opposite direction will release the tip.

3 Clains, 8 Drawing Figures England ..145/so B Q PATENTi-iflm 28 m2llillf i INVENTORS OWE WILHELM SUNDSTEN K65} BERTIL SUNE JOHANSSONATTORNEYS 1 SCREWDRIVER WITH AN EXCHANGEABLE TIP The present inventionrelates to a screwdriver with an exchangeable tip. In comparison withknown types of screwdrivers of this kind, the screwdriver according tothe present invention has the advantage of i.a. possessing essentiallythe same form as a common screwdriver without having any uncovered tipsecuring tongs or the like which weaken the screwdriver and easilybecome inoperable due to the penetration of dirt. The present inventionalso has the advantage of being simple and inexpensive to produce and ofenabling a robust design which is resistable to rough handling.

A preferred embodiment of screwdriver according to the invention isshown by way of example in the accompanying drawing.

FIG. 1 is a partially broken side-view of a screwdriver according to theinvention having a rod located in a sleeve and provided with anexchangeable tip,

FIG. 2 is a plan view of a portion of the rod having a wedge shapedforward end,

FIG. 3 shows the forward end portion of the rod seen from the side withan axial slit,

FIG. 4 is a separate view of the tip,

FIG. 5 is a partially broken view seen from above of the forward endportion of the screwdriver in FIG. 1,

FIG. 6 is a cross-section along line 6-6 in FIG. 5,

FIG. 7 shows on an enlarged scale the tip of FIG. .1, and

FIG. 8 shows another type of tip to be secured according to theinvention.

The screwdriver shown in FIG. 1 comprises an elongated handle 1 and arod 2 fixed in relation to said handle and extending coaxiallytherewith. The rod has a turned down rearward portion 3 which extendsinto a corresponding bore in the handle 1 and can be fixed in same byproviding the rearward end of said rod with a slot (not shown) whichconforms with an expanding element (not shown). The rod 2 can also befixed in the handle in another way, e.g., by casting.

The forward end of the rod 2 is milled down to a wedge shape with twosides 4, 5. In this part of the rod,

the rod has an essentially rectangular cross section. The

end of the rod is provided with an axial slit 6 to provide two legs 7, 8of a tong for securing an exchangeable tip 9 which is provided with arectangular fastening surface to be located between the legs 7, 8. Onthe outside of the rod 2 is a tubular sleeve 10, the forward end ofwhich is conically flattened at 11 to form a seat for the sides 4, 5 ofthe forward end of the rod 2. At its rearward end, the sleeve has anexternal thread 13 which cooperates with a corresponding internal thread13a in a control member 14 in the form of a nipple. This member 14 isjoumalled about that part of the turned down portion 3 of the rod 2which lies between the end of the handle 1 and a shoulder 2a of saidrod. It is seen that the control member 14 is hereby axially fixed anddisplaces the sleeve 10 when rotated in either direction, depending onthe direction of the rotation. The control member 14 is preferablyprovided with a handle portion 15 to be gripped by the fingers of the Iperson using the screwdriver.

When an exchange of tips is desired, the control member 14 need only berotated in one direction so that the sleeve l0 will be displaced to theleft and the legs 7, 8 release their grip on the tip 9 which can then beeasily removed. When a new tip is inserted, the control member 14 isrotated in the opposite direction so that the sleeve 10 is displaced tothe right instead. Thus, the inner sides of the sleeve s 10 taperingforward end portion 11 press on the sides 4, 5 of the rod 2 to effectcompression of the legs 7, 8 against the new tip. The tapering forwardend portion 11 of the sleeve 10 thus serves as a seat forthe legs 7, 8and concurrently prevents the sleeve 10 from rotating relative to therod 2 Currently used screwdriver tips are generally made with an edgewhose sides converge towards a point in front of the screwdriver. As aresult of this conicity, the

tipv has a tendency to leave the slot of the screw head during vigoroustightening. In order to overcome this drawback, the screwdriver tipsused together with the present screwdriver are preferably provided withedges whose side surfaces l6, l7 converge towards the handle of thescrewdriver when the tips are in position for use. This will be seenfrom FIG. 7.

FIG. 8 illustrates another tip 9a having teeth or edges 18 for screwswith heads provided with several radially extending, equally spacedgrooves in the head of the screw in a manner known per se.

The handle 1 may have one or more tip receiving chambers opening at therear end of the handle and closed by means of a detachable lid. Thus,anumber of equal or different tips may be stored in such chamber.

Within the scope of the invention, the sleeve 10 may befixed to thehandle, and the rod 2 may be axially displaceable relative to the sleeveand extend axially through the handle to a control member (not shown)which is rotatably joumalled at the rear end of the handle and adaptedto effect the axial displacement forwards and rearwards, respectively,by means of a threaded mechanism of principally the same type asdisclosed in connection with the threads 13 and 13a in FIG. 1. I

What we claim is:

l. A screwdriver with an exchangeable tip, characterized in that thehandle of the screwdriver supports a rod element coaxial with thehandle, and a sleeve element enclosing the rod' element, that theforward end portion of the rod element is providedwith an axial slit forreceiving the flat end of an exchangeable tip between two spaced legsforming the sides of the slit, that the legs taper towards the free endof the rod to form a wedge like member with two conically tapering outerside surfaces, that the forward end portion of the sleeve is formed totaper substantially in conformity with said legs to form a seat forthem, that one of said elements is secured to the handle and the otherelement is axially displaceable but non-rotatable relative to the firstelement and the handle, and that a threaded control member is rotatablymounted but substantially axially stationary relative to one of saidelements and has a thread cooperating with a thread on the other elementto effect axial displacement of said element when the control member isrotated in one direction to effect relative axial displacement of thesleeve member and rod element with the result that the legs engage theinner opposite sides of the forward tapering end portion of the sleevemember and are pressed against the flat end portion of a tip to secureit to the screwdriver 2. A screwdriver according to claim 1,characterized in that the rearward end portion of the rod element has ashoulder and a portion with a reduced diameter, that said reducedportion of the rod element is partially situated and secured in thehandle, and that a nipple is rotatably mounted on the reduced part ofthe rod lying outside the end of the handle, said nipple functioning asa rotatable control member and having an internal thread cooperatingwith an external thread on the sleeve, said nipple being held axiallysubstantially stationary relative to said handle by, on one side, oneend surface of the handle and, on the other side, by the in .that thetips intended for use together with the screwdriver have edges withopposite sides which converge in a direction towards the rear end of thetip which is flat to be received between the spaced legs of the forwardend of the rod.

1. A screwdriver with an exchangeable tip, characterized in that thehandle of the screwdriver supports a rod element coaxial with thehandle, and a sleeve element enclosing the rod element, that the forwardend portion of the rod element is provided with an axial slit forreceiving the flat end of an exchangeable tip between two spaced legsforming the sides of the slit, that the legs taper towards the free endof the rod to form a wedge like member with two conically tapering outerside surfaces, that the forward end portion of the sleeve is formed totaper substantially in conformity with said legs to form a seat forthem, that one of said elements is secured to the handle and the otherelement is axially displaceable but non-rotatable relative to the firstelement and the handle, and that a threaded control member is rotatablymounted but substantially axially stationary relative to one of saidelements and has a thread cooperating with a thread on the other elementto effect axial displacement of said element when the control member isrotated in one direction to effect relative axial displacement of thesleeve member and rod element with the result that the legs engage theinner opposite sides of the forward tapering end portion of the sleevemember and are pressed against the flat end portion of a tip to secureit to the screwdriver whereas rotation of the control member in oppositedirection will release the tip.
 2. A screwdriver according to claim 1,characterized in that the rearward end portion of the rod element has ashoulder and a portion with a Reduced diameter, that said reducedportion of the rod element is partially situated and secured in thehandle, and that a nipple is rotatably mounted on the reduced part ofthe rod lying outside the end of the handle, said nipple functioning asa rotatable control member and having an internal thread cooperatingwith an external thread on the sleeve, said nipple being held axiallysubstantially stationary relative to said handle by, on one side, oneend surface of the handle and, on the other side, by the shoulder formedbetween the thicker part and narrower parts of the rod element so thatwhen said nipple is rotated, it brings about an axial displacement ofthe sleeve element.
 3. A screwdriver according to claim 1, characterizedin that the tips intended for use together with the screwdriver haveedges with opposite sides which converge in a direction towards the rearend of the tip which is flat to be received between the spaced legs ofthe forward end of the rod.